Collard Greens

"Most people use the same rotation of lettuce and spinach," says Andrea Giancoli, RD, a spokesperson for the Academy of Nutrition and Dietetics, "so they miss out on some of the tastiest, most nutritious vegetables." Our greens guide is here to help.

Collard Greens

This mild staple of Southern cuisine may be better at lowering artery-clogging cholesterol than broccoli or spinach, research has shown.

Fresh ideas: Try a lighter take on collards, which are traditionally cooked with pork fat: Remove the stems and slice the leaves into two-inch pieces; meanwhile, fry turkey bacon in olive oil. Crumble bacon and sauté it with the collards and garlic. Add enough chicken stock to just cover the greens, reduce the heat to low, and simmer for an hour, or until tender. "Cooking collards for a long time breaks down the tough fibers," says Aliza Green, a chef in Philadelphia and the author of Field Guide to Produce. Finish the dish with a splash of apple cider vinegar and red pepper flakes.

Kale

This earthy, bitter green is sweeter in winter, but it's packed with nutrients year-round. Just one cup of raw kale supplies a day's worth of vitamins A and C and six times the daily requirement of bone-boosting vitamin K.

Fresh ideas: Make chips by stripping the leaves off the tough, inedible stems and tearing them into one-and-a-half-inch pieces. Toss with olive oil and salt and bake at 350 degrees for 10 to 15 minutes, or until crispy. For a simple no-cook side dish, slice kale into one-inch ribbons, add a tablespoon each of olive oil and lemon juice and a dash of salt; then gently massage with your fingertips until the leaves are wilted. Top with freshly ground black pepper, nuts or seeds for crunch, and either avocado slices or a sprinkle of pecorino.

Turnips

Avoid leaves that are wilted or yellow or have slick dark green patches.

When you cook turnips, don't throw out the tops, which have a strong flavor and cabbagelike texture. "They're loaded with fiber and vitamin K," says Maggie Moon, RD, a nutritionist for the New York City-based online grocer FreshDirect. One cup of the cooked greens fulfills 20 percent of the daily requirement for vitamin B6.

Fresh ideas: "Blanch turnip greens to soften their bite," Green says. "Then sauté them in olive oil with garlic and finish with a little lemon juice or apple cider vinegar." Or sauté garlic, onion, and lemon zest in olive oil; add turnip greens and white wine and simmer until soft. Then puree in a blender and serve as a dip with crusty bread.

Bok Choy

This mild, slightly sweet cousin of cabbage is a super source of calcium because it's low in oxalate, a compound in many greens that blocks absorption of the mineral. The veggie also has 25 kinds of cancer-fighting antioxidants called polyphenols, one study found.

Fresh ideas: Small, tender baby bok choy is great in stir-fries or tossed with oil, salt, and black pepper and roasted at 400 degrees for five minutes. If you're cooking the regular-size kind, make a side dish by chopping the stalks and sautéing them in oil with garlic, ginger, and reduced-sodium soy sauce for three to four minutes. "Then add the greens a few minutes before serving, so that the stalks are tender and the leaves are just wilted," Moon suggests.

Watercress

The small, oval-shaped leaves should smell peppery.

Watercress packs a healthy punch of vision-protecting carotenoids and compounds that may inhibit the growth of breast cancer tumors.

Fresh ideas: Trim the stems, then add the leaves to sandwiches, frittatas, and salads. "Pair watercress with a sweet balsamic vinaigrette," Giancoli says. Or transform a simple supper into dinner party fare by using fresh leaves as a bed for roast chicken or beef. To make soup, sauté a cubed potato and a diced onion, then simmer them in two cups each of low-fat milk and chicken stock for 10 minutes, or until tender. Add two cups of watercress (leaves and stems), cook five minutes more, and puree until smooth. Garnish with fresh watercress leaves and low-fat sour cream.

Swiss Chard

This somewhat salty relative of the beet is a top source of vitamins A and C. And one cup of cooked Swiss chard delivers more than 20 percent of your daily quota for iron.

Fresh ideas: "The stalks and the leaves are edible," Green says. To soften the leaves, blanch them by immersing in boiling salted water for a few minutes; then sauté with olive oil and garlic and toss with golden raisins. Or wrap seasoned fish fillets in the blanched leaves and bake. For a side dish, cook the stalks: Chop each into three or four pieces and boil in water with a squeeze of lemon juice for five minutes. Toss with olive oil and Parmesan; then broil for 10 minutes.

Escarole

Seek out tightly packed unblemished leaves.

It looks like romaine, but escarole's firm texture, paler color, and slightly bittersweet taste set it apart. At just eight calories per uncooked cup, this nutrition superstar supplies fiber and heart-healthy folate, along with vitamins A, C, and K.

Fresh ideas: "The inner leaves are sweet and mild, so they work well in salads," says Julia Sullivan, the chef at Haven's Kitchen, a cooking school and specialty food shop in New York City. To prep, use a paring knife to cut off a thin slice on the stem end, then remove the core. "Toss with olive oil, lemon juice, salt, and pepper and top with shaved Parmesan," she says. Add the outer leaves to minestrone and turkey chili for texture and flavor.

Prep School

When you get home from the supermarket or farmers' market, use this plan of action to make leaves last.

STEP 1: Trim

Chop off the stems or slice out the core, if there is one, and tear apart the leaves, discarding any that are brown or bruised.

STEP 2: Wash

To remove sand from sturdy greens, such as kale and collards, put them in a large bowl or clean sink filled with cold water. Swish vigorously to loosen grit, then scoop out the leaves; dirt will sink to the bottom. For delicate leaves, like watercress or bok choy, simply rinse carefully under running water.

STEP 3: Dry

Use a salad spinner, or spread a single layer of leaves on a clean towel. You want them only slightly damp, or they'll wilt.

STEP 4: Refrigerate

Roll up the towel and place it in a plastic produce bag from the grocery store; if you used a spinner, put dry leaves directly in the bag. Store greens in the crisper drawer, away from fruit. Certain fruits, like apples, pears, and avocados, emit ethylene, a gas that can hasten spoilage.

STEP 5: Revive

Although greens should last up to a week in the fridge, they may wilt. To perk them up, place them in a bowl of ice water for 15 minutes.